Methods and systems for re-securing a compromised channel in a satellite signal distribution environment

Abstract

A method implemented by a set top box that encrypts communications for a channel stacking switch (CS) using a public key of the CSS, the method comprising: obtaining a message from a head end; extracting electronic counter measure (ECM) data from the message; sending the ECM data to the CSS; receiving, in response to the sending, a new public key of the CSS; encrypting communications for the CSS using the new public key of the CSS. Also, a method for implementation by a CSS, comprising: maintaining a private key and a public key; obtaining ECM data sent by a set top box in communication with the CSS; obtaining an identifier of the CSS; formulating a new public key based on the private key, the identifier and the ECM; rendering the new public key available to the set top box.

What is claimed is: 
     
       1. A method for implementation by a channel stacking switch, comprising:
 maintaining a private key and a public key; 
 obtaining electronic counter measure (ECM) data sent by a set top box in communication with the channel stacking switch; 
 obtaining an identifier of the channel stacking switch; 
 formulating a new public key based on the private key, the identifier and the ECM data; 
 rendering the new public key available to the set top box. 
 
     
     
       2. The method defined in  claim 1 , further comprising managing a memory in which the private key, the public key and the new public key are stored. 
     
     
       3. The method defined in  claim 2 , further comprising replacing the public key with the new public key in the memory. 
     
     
       4. The method defined in  claim 1 , further comprising carrying out a pseudonymous signature scheme to formulate the new public key. 
     
     
       5. The method defined in  claim 1 , further comprising, prior to obtaining the ECM data, receiving a message from a head end and forwarding the message to the set top box, the message comprising the ECM data. 
     
     
       6. The method defined in  claim 1 , wherein the identifier of the channel stacking switch comprises a hardware identifier. 
     
     
       7. The method defined in  claim 1 , further comprising decrypting data received from the set top box using the private key. 
     
     
       8. The method defined in  claim 7 , wherein prior to obtaining the ECM data, at least some of the data received from the set top box is encrypted using the public key and after rendering the new public key available to the set top box, at least some of the data received from the set top box is encrypted using the new public key. 
     
     
       9. A channel stacking switch, comprising:
 a memory configured to maintain a private key and a public key; 
 a communications interface configured to communicate with a set top box over a communication channel and also configured to receive data sent from a head end over a satellite link; 
 a processing entity configured to obtain via the communication interface electronic counter measure (ECM) data sent by the set top box, obtain an identifier of the channel stacking switch; formulate a new public key based on the private key, the identifier and the ECM data and send the new public key to the set top box.